Set Appliance State:

Turn Hot Water Tap On
DHW thermostat set to 3 o'clock position
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Enter the status code display mode.
(Press the top "i" button once briefly)
Is status code S.53 or S.54 shown?
Note:
To exit the status code mode press the "i" button once briefly.